Method and apparatus for high rank multiple-input multiple-output (mimo) symbol detection

ABSTRACT

A method and an apparatus in a multiple-input multiple-output (MIMO) wireless communication system are provided. A signal is received over a channel. The channel is decomposed into a plurality of virtual channels. Symbol detection is performed on each of the plurality of virtual channels. Values are obtained for the channel. Decoding is performed using the values to output a decoded symbol value of the received signal.

PRIORITY

This application is a Continuation Application of U.S. patentapplication Ser. No. 16/273,632, filed in the U.S. Patent and TrademarkOffice on Feb. 12, 2019, which is based on and claims priority under 35U.S.C. § 119(e) to a U.S. Provisional patent application filed on Dec.3, 2018 in the United States Patent and Trademark Office and assignedSer. No. 62/774,554, the contents of which are incorporated herein byreference.

FIELD

The present disclosure relates generally to a wireless communicationsystem, and more particularly, to a method and an apparatus for highrank multiple-input multiple-output (MIMO) symbol detection.

BACKGROUND

A typical modem of an electronic device includes a symbol detector fordetermining log-likelihood-ratio (LLR) values of coded bits fromreceived signals. These LLR values are used by a decoder of the modem torecover uncoded bits. When the number of layers (i.e., the rank) usedfor multiple-input multiple-output (MIMO) transmission increases, thecomplexity of symbol detection may increase significantly. In long termevolution (LTE) (Release 10) and fifth generation (5G) (Release 15), amaximum of eight transmit and eight receive antennas or panels aresupported. Accordingly, 8×8 or rank-8 symbol detectors are required.

Existing MIMO symbol detectors include, for example, maximum likelihood(ML), zero-forcing (ZF), minimum mean square error (MMSE),ZF/MMSE-successive interference cancellation (MMSE-SIC), and spheredecoder (SD) detectors. For high rank scenarios, such as rank-8,existing linear symbol detectors, such as, for example, ZF and MMSEdetectors, have degraded performance due to their simple architecture.Existing non-linear symbol detectors, such as, for example, ML,ZF/MMSE-SIC, and SD detectors, may perform well but are too complex tobe implemented. For example, ML detection requires that all symbols in aconstellation are considered for LLR value calculation.

SUMMARY

According to one embodiment, a method of operating an electronic devicein a MIMO wireless communication system is provided. A signal isreceived over a channel. The channel is decomposed into a plurality ofvirtual channels. Symbol detection is performed on each of the pluralityof virtual channels. Values for the channel are obtained. Decoding isperformed using the values to output a decoded symbol value of thereceived signal.

According to one embodiment, an electronic device is provided. Theelectronic device includes a processor and a non-transitory computerreadable storage medium storing instructions that, when executed, causethe processor to receive a signal over a channel, decompose the channelinto a plurality of virtual channels, and perform symbol detection oneach of the plurality of virtual channels. The instructions, whenexecuted, also cause the processor to obtain values for the channel, andperform decoding using the values to output a decoded symbol value ofthe received signal.

According to one embodiment, a multiple-input multiple-output symboldetector of an electronic device is provided. The detector includes oneor more preprocessors configured to decompose a channel, over which asignal is received, into a plurality of virtual channels. The detectoralso includes a plurality of symbol detectors configured to performsymbol detection on each of the plurality of virtual channels.Additionally, the detector includes a combiner configured to obtainvalues for the channel. The detector further includes a decoderconfigured to decode the values and output a decoded symbol value of thereceived signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing detailed description, taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a diagram illustrating a high rank symbol detector implementedwith multiple lower rank symbol detectors, according to one embodiment;

FIG. 2 is a diagram illustrating a rank-8 symbol detector implementedusing three rank-4 symbol detectors, according to one embodiment;

FIG. 3 is a diagram illustrating a rank-4 symbol detector implementedwith one rank-4 symbol detector and two rank-2 symbol detectors,according to one embodiment;

FIG. 4 is a flow chart illustrating a method for high rank symboldetection, according to one embodiment; and

FIG. 5 is a diagram illustrating an electronic device in a networkenvironment, according to one embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure are described indetail with reference to the accompanying drawings. It should be notedthat the same elements will be designated by the same reference numeralsalthough they are shown in different drawings. In the followingdescription, specific details such as detailed configurations andcomponents are merely provided to assist with the overall understandingof the embodiments of the present disclosure. Therefore, it should beapparent to those skilled in the art that various changes andmodifications of the embodiments described herein may be made withoutdeparting from the scope of the present disclosure. In addition,descriptions of well-known functions and constructions are omitted forclarity and conciseness. The terms described below are terms defined inconsideration of the functions in the present disclosure, and may bedifferent according to users, intentions of the users, or customs.Therefore, the definitions of the terms should be determined based onthe contents throughout this specification.

The present disclosure may have various modifications and variousembodiments, among which embodiments are described below in detail withreference to the accompanying drawings. However, it should be understoodthat the present disclosure is not limited to the embodiments, butincludes all modifications, equivalents, and alternatives within thescope of the present disclosure.

Although the terms including an ordinal number such as first, second,etc. may be used for describing various elements, the structuralelements are not restricted by the terms. The terms are only used todistinguish one element from another element. For example, withoutdeparting from the scope of the present disclosure, a first structuralelement may be referred to as a second structural element. Similarly,the second structural element may also be referred to as the firststructural element. As used herein, the term “and/or” includes any andall combinations of one or more associated items.

The terms used herein are merely used to describe various embodiments ofthe present disclosure but are not intended to limit the presentdisclosure. Singular forms are intended to include plural forms unlessthe context clearly indicates otherwise. In the present disclosure, itshould be understood that the terms “include” or “have” indicate theexistence of a feature, a number, a step, an operation, a structuralelement, parts, or a combination thereof, and do not exclude theexistence or probability of the addition of one or more other features,numerals, steps, operations, structural elements, parts, or combinationsthereof.

Unless defined differently, all terms used herein have the same meaningsas those understood by a person skilled in the art to which the presentdisclosure belongs. Terms such as those defined in a generally useddictionary are to be interpreted to have the same meanings as thecontextual meanings in the relevant field of art, and are not to beinterpreted to have ideal or excessively formal meanings unless clearlydefined in the present disclosure.

The electronic device according to one embodiment may be one of varioustypes of electronic devices. The electronic devices may include, forexample, a portable communication device (e.g., a smart phone), acomputer, a portable multimedia device, a portable medical device, acamera, a wearable device, or a home appliance. According to oneembodiment of the disclosure, an electronic device is not limited tothose described above.

The terms used in the present disclosure are not intended to limit thepresent disclosure but are intended to include various changes,equivalents, or replacements for a corresponding embodiment. With regardto the descriptions of the accompanying drawings, similar referencenumerals may be used to refer to similar or related elements. A singularform of a noun corresponding to an item may include one or more of thethings, unless the relevant context clearly indicates otherwise. As usedherein, each of such phrases as “A or B,” “at least one of A and B,” “atleast one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and“at least one of A, B, or C,” may include all possible combinations ofthe items enumerated together in a corresponding one of the phrases. Asused herein, terms such as “1^(st),” “2nd,” “first,” and “second” may beused to distinguish a corresponding component from another component,but are not intended to limit the components in other aspects (e.g.,importance or order). It is intended that if an element (e.g., a firstelement) is referred to, with or without the term “operatively” or“communicatively”, as “coupled with,” “coupled to,” “connected with,” or“connected to” another element (e.g., a second element), it indicatesthat the element may be coupled with the other element directly (e.g.,wired), wirelessly, or via a third element.

As used herein, the term “module” may include a unit implemented inhardware, software, or firmware, and may interchangeably be used withother terms, such as, for example, “logic,” “logic block,” “part,” and“circuitry.” A module may be a single integral component, or a minimumunit or part thereof, adapted to perform one or more functions. Forexample, according to one embodiment, a module may be implemented in aform of an application-specific integrated circuit (ASIC).

According to embodiments of the present disclosure, virtual channelcombining (VCC) is performed using several lower rank symbol detectors,and resulting Euclidean distance (ED) values or LLR values are combined,to fulfill the need for a high rank symbol detector. VCC introducesanother form of diversity gain in forming multiple virtual channels, bypreprocessing different selected layers of a channel over which a signalis received, for each virtual channel. Accordingly, low complexity andhigh flexibility are achieved for a high rank MIMO receiver. The systemmay utilize any type of symbol detector, having any rank at or belowthat of the channel, in any combination. For example, a rank-8 symboldetector can be implemented with 2 or more rank-4 symbol detectors.Alternatively, a rank-8 symbol detector can be implemented with 4 ormore rank-2 symbol detectors.

FIG. 1 is a diagram illustrating a high rank symbol detector implementedwith multiple lower rank symbol detectors, according to one embodiment.Given a signal received over a high rank channel, preprocessing isperformed at preprocessors 102-1, 102-2, through 102-n to decompose thehigh rank channel into several virtual channels with lower ranks. Oneexample of a signal preprocessing scheme is interference whitening (IW).Other preprocessing schemes include, for example, interferencecancellation, interference ignorance, and block based IW. The layers ofthe original high rank channel that remain in each virtual channel aftersignal preprocessing are referred to as detection layers, which areprovided from each of preprocessors 102-1, 102-2, through 102-n torespective lower rank symbol detectors 104-1, 104-2, through 104-n.Lower rank symbol detection is then performed on the correspondingdetection layers. The outputs of the lower rank symbol detectors 104-1,104-2, through 104-n are ED values or LLR values for the detectionlayers. An ED value combining scheme or an LLR value combining scheme isperformed at a combiner 106 to obtain final LLR values, corresponding tolayers of the channel. A decoder 108 uses the final LLR values to obtaina decoded symbol value for the received signal.

Several ED or LLR combining schemes are described in greater detailbelow. However, embodiments of the present disclosure are not restrictedto LLR combining schemes and ED combining schemes.

One such LLR combining scheme is LLR summation in which severalcorresponding bit LLR values for different lower rank symbol detectorsare summed to obtain the final LLR for that specific bit. Another LLRcombining scheme is LLR mean in which several corresponding bit LLRvalues for different lower rank symbol detectors are used to calculateits mean to obtain the final LLR value for that specific bit. Differentmean calculation schemes can be applied, such as, for example, algebraicand geometric means. An additional LLR combining scheme is LLR selectionin which, among several corresponding bit LLR values for different lowerrank symbol detectors, only one LLR is selected to obtain the final LLRfor that specific bit. The LLR with the largest absolute value isusually selected. However, other selection schemes may also be applied.

In ED combining, final EDs of 0 and 1 of each bit position of amodulation symbol are determined by the minimum corresponding EDs fromdifferent lower rank symbol detectors. Final LLR=minED(1)−minED(0),where minED(1) and minED(0) are final minimum ED of bit 1 and bit 0 of aspecific bit position of a specific modulation symbol.

Referring now to FIG. 2, a diagram illustrates a rank-8 symbol detectorimplemented using three rank-4 symbol detectors, according to oneembodiment.

A rank-8 channel includes a first codeword (CW0), corresponding tolayers 1-4 of the channel, and a second codeword (CW1), corresponding tolayers 5-8 of the channel. FIG. 2 Illustrates the processing of CW0,corresponding to layers 1-4 of the channel. Using IW as a preprocessingscheme, multiple virtual channels are generated at preprocessors 202-1,202-2, and 202-3. For example, at first preprocessor 202-1, IW isperformed on layers [5 6 7 8], resulting in detection layers [1, 2, 3,4]. At second preprocessor 202-2, IW is performed on layers [3, 4, 7,8], resulting in detection layers [1, 2, 5, 6]. At third preprocessor202-3, IW is performed on layers [1, 2, 5, 6], resulting in detectionlayers [3, 4, 7, 8].

Each virtual channel is provided to a rank-4 symbol detector. Forexample, symbol detection is performed on detection layers [1, 2, 3, 4]at first rank-4 symbol detector 204-1. Symbol detection is performed ondetection layers [1, 2, 5, 6] at second rank-4 symbol detector 204-2.Symbol detection is performed on detection layers [3, 4, 7, 8] at thirdrank-4 symbol detector 204-3. First through third rank-4 symboldetectors 204-1, 204-2, and 204-3 generate LLR values (or ED values) forthe layers of CW0 (e.g., [1, 2, 3, 4], [1, 2], and [3, 4]).

The LLR values (or ED values) are combined at a combiner 206 using anLLR combining scheme (or ED combining scheme), and the resulting finalLLR values are fed from the combiner 206 to a decoder 208 to provide adecoded symbol value of the received signal. Using more virtual channelshelps to further improve performance.

Second rank-4 symbol detector 204-2 and third rank-4 symbol detector204-3 have byproduct LLR values for layers [5, 6] and [7, 8] of thechannel, respectively. Although these LLR values are not useful indecoding CW0, they may be saved and used in the subsequent decoding ofCW1.

The ranks of the lower rank symbol detectors and the layers forpreprocessing may be selected in various ways, such as, for example,fixed selection based on experience or simulation results, and dynamicselection based on metrics (e.g., power of preprocessed layers) or priorknowledge of channel profiles.

The ranks of the lower rank symbol detectors are not required to be thesame. Furthermore, the ranks of some lower rank symbol detectors are notnecessarily smaller than the rank of the channel.

FIG. 3 is a diagram illustrating a rank-4 symbol detector implementedwith one rank-4 symbol detector and two rank-2 symbol detectors,according to one embodiment.

Using IW as a preprocessing scheme, multiple virtual channels aregenerated. At first preprocessor 302-1, IW is performed on layers [3, 4]of the channel, resulting in detection layers [1, 2]. At secondpreprocessor 302-2, IW is performed on layers [1, 2] of the channel,resulting in detection layers [3, 4]. Layers [1, 2, 3, 4] of the channelare directly fed to rank-4 symbol detector 304-1 without preprocessing.

Symbol detection is performed on detection layers [1, 2, 3, 4] at therank-4 symbol detector 304-1. Symbol detection is performed on detectionlayers [1, 2] at first rank-2 symbol detector 304-2. Symbol detection isperformed on detection layers [3, 4] at second rank-2 symbol detector304-3. Symbol detectors 304-1, 304-2, and 304-3 generate LLR values (orED values) for the layers (e.g., [1, 2, 3, 4], [1, 2], and [3, 4]).

The LLR values (or ED values) are combined at a combiner 306 using anLLR combining scheme (or an ED combining scheme), and the resultingfinal LLR values are fed from the combiner 306 to a decoder 308 toprovide a decoded symbol value of the received signal.

FIG. 4 is a flow chart illustrating a method for high-rank symboldetection, according to one embodiment.

A modem of an electronic device receives a signal over a channel at 402.Preprocessors decompose the channel into virtual channels via a signalpreprocessing scheme at 404. At least one of the virtual channels has arank lower than that of the channel over which the signal is received.Additionally, different combinations of layers of the channel arepreprocessed for each of the virtual channels. Respective symboldetectors perform symbol detection on each of the virtual channels at406. At least one symbol detector has a rank that is lower than that ofthe channel over which the signal is received. The output from eachsymbol detector includes LLR values or ED values for the correspondinglayers processed at each symbol detector. A combiner combines outputfrom the plurality of symbol detectors to obtain final LLR values forlayers of the channel over which the signal is received at 408. Adecoder performs decoding using the final LLR values to output a decodedsymbol value for the signal received over the channel at 410.

According to one embodiment, the present apparatus includes a high-rankmultiple-input, multiple output (MIMO) symbol detector configured todetect symbols of a signal received over a channel. The high-rank MIMOsymbol detector includes one or more preprocessors each configured todecompose the N-rank channel into several virtual channels. Each virtualchannel may have a rank less than N. Preprocessing may be performed bywhitening one or more layers of the N-rank channel, and outputtingremaining un-whitened layers. The high-rank MIMO symbol detector alsoincludes one or more lower-rank detectors configured to perform symboldetection of the remaining un-whitened layers for a virtual channel. Thehigh-rank MIMO symbol detector also includes a combiner configured tocombine an output of each lower-rank detector and output a combinedresult. The output of each lower-rank detector may be ED values or LLRvalues corresponding to layers of the channel over which the signal isreceived. The high-rank MIMO symbol detector further includes a decoderconfigured to output a decoded symbol value of the signal based on thecombined result.

FIG. 5 is a block diagram of an electronic device in a networkenvironment, according to one embodiment. Referring to FIG. 5, anelectronic device 501 in a network environment 500 may communicate withan electronic device 502 via a first network 598 (e.g., a short-rangewireless communication network), or an electronic device 504 or a server508 via a second network 599 (e.g., a long-range wireless communicationnetwork). The electronic device 501 may communicate with the electronicdevice 504 via the server 508. The electronic device 501 may include aprocessor 520, a memory 530, an input device 550, a sound output device555, a display device 560, an audio module 570, a sensor module 576, aninterface 577, a haptic module 579, a camera module 580, a powermanagement module 588, a battery 589, a communication module 590, asubscriber identification module (SIM) 596, or an antenna module 597. Inone embodiment, at least one (e.g., the display device 560 or the cameramodule 580) of the components may be omitted from the electronic device501, or one or more other components may be added to the electronicdevice 501. In one embodiment, some of the components may be implementedas a single integrated circuit (IC). For example, the sensor module 576(e.g., a fingerprint sensor, an iris sensor, or an illuminance sensor)may be embedded in the display device 560 (e.g., a display).

The processor 520 may execute, for example, software (e.g., a program540) to control at least one other component (e.g., a hardware or asoftware component) of the electronic device 501 coupled with theprocessor 520, and may perform various data processing or computations.As at least part of the data processing or computations, the processor520 may load a command or data received from another component (e.g.,the sensor module 576 or the communication module 590) in volatilememory 532, process the command or the data stored in the volatilememory 532, and store resulting data in non-volatile memory 534. Theprocessor 520 may include a main processor 521 (e.g., a centralprocessing unit (CPU) or an application processor (AP)), and anauxiliary processor 523 (e.g., a graphics processing unit (GPU), animage signal processor (ISP), a sensor hub processor, or a communicationprocessor (CP)) that is operable independently from, or in conjunctionwith, the main processor 521. Additionally or alternatively, theauxiliary processor 523 may be adapted to consume less power than themain processor 521, or execute a particular function. The auxiliaryprocessor 523 may be implemented as being separate from, or a part of,the main processor 521.

The auxiliary processor 523 may control at least some of the functionsor states related to at least one component (e.g., the display device560, the sensor module 576, or the communication module 590) among thecomponents of the electronic device 501, instead of the main processor521 while the main processor 521 is in an inactive (e.g., sleep) state,or together with the main processor 521 while the main processor 521 isin an active state (e.g., executing an application). According to oneembodiment, the auxiliary processor 523 (e.g., an image signal processoror a communication processor) may be implemented as part of anothercomponent (e.g., the camera module 580 or the communication module 590)functionally related to the auxiliary processor 523.

The memory 530 may store various data used by at least one component(e.g., the processor 520 or the sensor module 576) of the electronicdevice 501. The various data may include, for example, software (e.g.,the program 540) and input data or output data for a command relatedthereto. The memory 530 may include the volatile memory 532 or thenon-volatile memory 534.

The program 540 may be stored in the memory 530 as software, and mayinclude, for example, an operating system (OS) 542, middleware 544, oran application 546.

The input device 550 may receive a command or data to be used by othercomponent (e.g., the processor 520) of the electronic device 501, fromthe outside (e.g., a user) of the electronic device 501. The inputdevice 550 may include, for example, a microphone, a mouse, or akeyboard.

The sound output device 555 may output sound signals to the outside ofthe electronic device 501. The sound output device 555 may include, forexample, a speaker or a receiver. The speaker may be used for generalpurposes, such as playing multimedia or recording, and the receiver maybe used for receiving an incoming call. According to one embodiment, thereceiver may be implemented as being separate from, or a part of, thespeaker.

The display device 560 may visually provide information to the outside(e.g., a user) of the electronic device 501. The display device 560 mayinclude, for example, a display, a hologram device, or a projector andcontrol circuitry to control a corresponding one of the display,hologram device, and projector. According to one embodiment, the displaydevice 560 may include touch circuitry adapted to detect a touch, orsensor circuitry (e.g., a pressure sensor) adapted to measure theintensity of force incurred by the touch.

The audio module 570 may convert a sound into an electrical signal andvice versa. According to one embodiment, the audio module 570 may obtainthe sound via the input device 550, or output the sound via the soundoutput device 555 or a headphone of an external electronic device 502directly (e.g., wired) or wirelessly coupled with the electronic device501.

The sensor module 576 may detect an operational state (e.g., power ortemperature) of the electronic device 501 or an environmental state(e.g., a state of a user) external to the electronic device 501, andthen generate an electrical signal or data value corresponding to thedetected state. The sensor module 576 may include, for example, agesture sensor, a gyro sensor, an atmospheric pressure sensor, amagnetic sensor, an acceleration sensor, a grip sensor, a proximitysensor, a color sensor, an infrared (IR) sensor, a biometric sensor, atemperature sensor, a humidity sensor, or an illuminance sensor.

The interface 577 may support one or more specified protocols to be usedfor the electronic device 501 to be coupled with the external electronicdevice 502 directly (e.g., wired) or wirelessly. According to oneembodiment, the interface 577 may include, for example, a highdefinition multimedia interface (HDMI), a universal serial bus (USB)interface, a secure digital (SD) card interface, or an audio interface.

A connecting terminal 578 may include a connector via which theelectronic device 501 may be physically connected with the externalelectronic device 502. According to one embodiment, the connectingterminal 578 may include, for example, an HDMI connector, a USBconnector, an SD card connector, or an audio connector (e.g., aheadphone connector).

The haptic module 579 may convert an electrical signal into a mechanicalstimulus (e.g., a vibration or a movement) or an electrical stimuluswhich may be recognized by a user via tactile sensation or kinestheticsensation. According to one embodiment, the haptic module 579 mayinclude, for example, a motor, a piezoelectric element, or an electricalstimulator.

The camera module 580 may capture a still image or moving images.According to one embodiment, the camera module 580 may include one ormore lenses, image sensors, image signal processors, or flashes.

The power management module 588 may manage power supplied to theelectronic device 501. The power management module 588 may beimplemented as at least part of, for example, a power managementintegrated circuit (PMIC).

The battery 589 may supply power to at least one component of theelectronic device 501. According to one embodiment, the battery 589 mayinclude, for example, a primary cell which is not rechargeable, asecondary cell which is rechargeable, or a fuel cell.

The communication module 590 may support establishing a direct (e.g.,wired) communication channel or a wireless communication channel betweenthe electronic device 501 and the external electronic device (e.g., theelectronic device 502, the electronic device 504, or the server 508) andperforming communication via the established communication channel. Thecommunication module 590 may include one or more communicationprocessors that are operable independently from the processor 520 (e.g.,the AP) and supports a direct (e.g., wired) communication or a wirelesscommunication. According to one embodiment, the communication module 590may include a wireless communication module 592 (e.g., a cellularcommunication module, a short-range wireless communication module, or aglobal navigation satellite system (GNSS) communication module) or awired communication module 594 (e.g., a local area network (LAN)communication module or a power line communication (PLC) module). Acorresponding one of these communication modules may communicate withthe external electronic device via the first network 598 (e.g., ashort-range communication network, such as Bluetooth, wireless-fidelity(Wi-Fi) direct, or a standard of the Infrared Data Association (IrDA))or the second network 599 (e.g., a long-range communication network,such as a cellular network, the Internet, or a computer network (e.g.,LAN or wide area network (WAN)). These various types of communicationmodules may be implemented as a single component (e.g., a single IC), ormay be implemented as multiple components (e.g., multiple ICs) that areseparate from each other. The wireless communication module 592 mayidentify and authenticate the electronic device 501 in a communicationnetwork, such as the first network 598 or the second network 599, usingsubscriber information (e.g., international mobile subscriber identity(IMSI)) stored in the subscriber identification module 596.

The antenna module 597 may transmit or receive a signal or power to orfrom the outside (e.g., the external electronic device) of theelectronic device 501. According to one embodiment, the antenna module597 may include one or more antennas, and, therefrom, at least oneantenna appropriate for a communication scheme used in the communicationnetwork, such as the first network 598 or the second network 599, may beselected, for example, by the communication module 590 (e.g., thewireless communication module 592). The signal or the power may then betransmitted or received between the communication module 590 and theexternal electronic device via the selected at least one antenna.

At least some of the above-described components may be mutually coupledand communicate signals (e.g., commands or data) therebetween via aninter-peripheral communication scheme (e.g., a bus, a general purposeinput and output (GPIO), a serial peripheral interface (SPI), or amobile industry processor interface (MIPI)).

According to one embodiment, commands or data may be transmitted orreceived between the electronic device 501 and the external electronicdevice 504 via the server 508 coupled with the second network 599. Eachof the electronic devices 502 and 504 may be a device of a same type as,or a different type, from the electronic device 501. All or some ofoperations to be executed at the electronic device 501 may be executedat one or more of the external electronic devices 502, 504, or 508. Forexample, if the electronic device 501 should perform a function or aservice automatically, or in response to a request from a user oranother device, the electronic device 501, instead of, or in additionto, executing the function or the service, may request the one or moreexternal electronic devices to perform at least part of the function orthe service. The one or more external electronic devices receiving therequest may perform the at least part of the function or the servicerequested, or an additional function or an additional service related tothe request, and transfer an outcome of the performing to the electronicdevice 501. The electronic device 501 may provide the outcome, with orwithout further processing of the outcome, as at least part of a replyto the request. To that end, a cloud computing, distributed computing,or client-server computing technology may be used, for example.

One embodiment may be implemented as software (e.g., the program 540)including one or more instructions that are stored in a storage medium(e.g., internal memory 536 or external memory 538) that is readable by amachine (e.g., the electronic device 501). For example, a processor ofthe electronic device 501 may invoke at least one of the one or moreinstructions stored in the storage medium, and execute it, with orwithout using one or more other components under the control of theprocessor. Thus, a machine may be operated to perform at least onefunction according to the at least one instruction invoked. The one ormore instructions may include code generated by a complier or codeexecutable by an interpreter. A machine-readable storage medium may beprovided in the form of a non-transitory storage medium. The term“non-transitory” indicates that the storage medium is a tangible device,and does not include a signal (e.g., an electromagnetic wave), but thisterm does not differentiate between where data is semi-permanentlystored in the storage medium and where the data is temporarily stored inthe storage medium.

According to one embodiment, a method of the disclosure may be includedand provided in a computer program product. The computer program productmay be traded as a product between a seller and a buyer. The computerprogram product may be distributed in the form of a machine-readablestorage medium (e.g., a compact disc read only memory (CD-ROM)), or bedistributed (e.g., downloaded or uploaded) online via an applicationstore (e.g., Play Store™), or between two user devices (e.g., smartphones) directly. If distributed online, at least part of the computerprogram product may be temporarily generated or at least temporarilystored in the machine-readable storage medium, such as memory of themanufacturer's server, a server of the application store, or a relayserver.

According to one embodiment, each component (e.g., a module or aprogram) of the above-described components may include a single entityor multiple entities. One or more of the above-described components maybe omitted, or one or more other components may be added. Alternativelyor additionally, a plurality of components (e.g., modules or programs)may be integrated into a single component. In this case, the integratedcomponent may still perform one or more functions of each of theplurality of components in the same or similar manner as they areperformed by a corresponding one of the plurality of components beforethe integration. Operations performed by the module, the program, oranother component may be carried out sequentially, in parallel,repeatedly, or heuristically, or one or more of the operations may beexecuted in a different order or omitted, or one or more otheroperations may be added.

Although certain embodiments of the present disclosure have beendescribed in the detailed description of the present disclosure, thepresent disclosure may be modified in various forms without departingfrom the scope of the present disclosure. Thus, the scope of the presentdisclosure shall not be determined merely based on the describedembodiments, but rather determined based on the accompanying claims andequivalents thereto.

What is claimed is:
 1. A method of operating an electronic device in amultiple-input multiple-output (MIMO) wireless communication system, themethod comprising: receiving a signal over a channel; decomposing thechannel into a plurality of virtual channels; performing symboldetection on each of the plurality of virtual channels; obtaining valuesfor the channel; and performing decoding using the values to output adecoded symbol value for the received signal.
 2. The method of claim 1,wherein at least one of the plurality of virtual channels has a lowerrank than that of the channel.
 3. The method of claim 1, wherein, indecomposing the channel, a different combination of layers, from amongthe layers of the channel, is preprocessed for each of the plurality ofvirtual channels.
 4. The method of claim 1, wherein the channel isdecomposed via a signal preprocessing scheme comprising at least one ofinterference whitening, interference cancellation, interferenceignorance, and block based interference whitening.
 5. The method ofclaim 1, wherein symbol detection is performed using respective symboldetectors.
 6. The method of claim 5, wherein each of the symboldetectors has a lower rank than that of the channel.
 7. The method ofclaim 5, wherein: the channel is a rank-8 channel and the symboldetectors comprise a plurality of rank-4 symbol detectors or a pluralityof rank-2 symbol detectors; or the channel is a rank-4 channel and thesymbol detectors comprise a rank-4 symbol detector and a plurality ofrank-2 symbol detectors.
 8. The method of claim 5, wherein the symboldetectors comprise at least one of a maximum likelihood detector,zero-forcing (ZF) detector, minimum mean square error (MMSE) detector,ZF/MMSE-successive interference cancellation detector, and spheredecoder detector.
 9. The method of claim 5, wherein the output from eachof the symbol detectors comprises initial log likelihood ratio (LLR)values or Euclidean distance (ED) values for a respective combination oflayers, from among the layers of the channel.
 10. The method of claim 9,wherein, when the output comprises LLR values, the output is combinedusing LLR summation, LLR mean, or LLR selection.
 11. The method of claim9, wherein, when the output comprises ED values, the output is combinedusing ED combining.
 12. An electronic device, comprising: a processor;and a non-transitory computer readable storage medium storinginstructions that, when executed, cause the processor to: receive asignal over a channel; decompose the channel into a plurality of virtualchannels; perform symbol detection on each of the plurality of virtualchannels; obtain values for the channel; and perform decoding using thevalues to output a decoded symbol value of the received signal.
 13. Theelectronic device of claim 12, wherein at least one of the plurality ofvirtual channels has a lower rank than that of the channel.
 14. Theelectronic device of claim 12, wherein, in decomposing the channel, adifferent combination of layers, from among the layers of the channel,is preprocessed for each of the plurality of virtual channels.
 15. Theelectronic device of claim 12, wherein symbol detection is performedusing respective symbol detectors.
 16. The electronic device of claim15, wherein each of the symbol detectors has a lower rank than that ofthe channel.
 17. The electronic device of claim 15, wherein: the channelis a rank-8 channel and the symbol detectors comprise a plurality ofrank-4 symbol detectors or a plurality of rank-2 symbol detectors; orthe channel is a rank-4 channel and the symbol detectors comprise arank-4 symbol detector and a plurality of rank-2 symbol detectors. 18.The electronic device of claim 15, wherein the output from each of thesymbol detectors comprises initial LLR values or Euclidean distance (ED)values for a respective combination of layers, from among the layers ofthe channel.
 19. The electronic device of claim 18, wherein: when theoutput comprises initial LLR values, the output is combined using LLRsummation, LLR mean, or LLR selection; and when the output comprises EDvalues, the output is combined using ED combining.
 20. A multiple-inputmultiple-output symbol detector of an electronic device, themultiple-input multiple-output symbol detector comprising: one or morepreprocessors configured to decompose a channel, over which a signal isreceived, into a plurality of virtual channels; a plurality of symboldetectors configured to perform symbol detection on each of theplurality of virtual channels; a combiner configured to obtain valuesfor the channel; and a decoder configured to decode the values andoutput a decoded symbol value of the received signal.